1. Field of the Invention
The present invention relates to a control apparatus for a vehicular electric component which controls an electric component attached to a vehicle, and which has a diagnosis function for determining whether or not an anomaly has occurred in the electric component.
2. Description of the Related Art
In an automobile, various electric components, such as a gas sensor, a glow plug and a temperature sensor, are used. A control apparatus which controls such an electric component has a diagnosis function for determining whether or not an anomaly has occurred in the electric component.
In general, a program for anomaly diagnosis is installed in ROM within a microcomputer mounted in a control apparatus, along with a program for controlling the electronic component and other programs. Meanwhile, such a control apparatus is attached to various types of automotive engines, which are controlled by various types of control systems. Therefore, the manner of use of an electric component (for example, application voltage or the like) may change depending on the type of engine and control system to be used. An anomaly diagnosis program having specifications suitable for the type of engine and control system is designed and used.
However, if a dedicated anomaly diagnosis program is prepared for each combination of an engine and control system type, development of the anomaly diagnosis program requires increased man-hours and increased labor. In order to solve such a problem, a control apparatus has been proposed in which an anomaly diagnosis program of an object oriented design is installed (for example, see Patent Document 1). That is, minimum unit programs (anomaly diagnosis functions) which correspond to various types of engines and/or control systems are designed, and an anomaly diagnosis program is prepared by combining necessary programs in accordance with an engine and a control system in which the anomaly diagnosis program is to be installed.
[Patent Document 1] Japanese Patent Application Laid-Open (kokai) No. 2000-97810
3. Problems to be Solved by the Invention
However, a conventional control apparatus has the following problem. For example, in some cases, operation of an anomaly diagnosis function is checked and/or a durability test for an electric component is performed in a state in which a control apparatus is installed in an automobile. In some cases, such a test is performed in a state in which a certain anomaly diagnosis function is temporarily stopped. In the case of the control apparatus disclosed in Patent Document 1, an anomaly diagnosis program is installed in the ROM of the control apparatus. Therefore, when a certain anomaly diagnosis function is to be stopped, it is necessary to prepare an anomaly diagnosis program including a new combination of anomaly diagnosis functions not including the certain anomaly diagnosis function, and to re-install the anomaly diagnosis program.